The present invention relates to a process for avoiding formation of smoke and flames in bottom blown converters upon charging of pig iron and scrap, deslagging and casting.
In addition to optimum collecting of reaction gases during actual blowing periods, it is essential in bottom blown oxygen crucibles to avoid formation of smoke and flames, occurring upon charging of ingredient materials, as well as escape of smoke and flames into the furnace room.
For solving this problem, the most favorable conditions are present in bottom blown oxygen crucibles, in contradistinction to opinions previously held by experts in this art.
In the process for refining pig iron in a bottom blown converter in which pure oxygen and a nitrogen free blanket gas are blown into molten pig iron by tuyeres, it is already known to preheat the scrap also by introduction of oxygen and hydrocarbons. For this purpose there are used the same tuyeres in one half of the converter bottom which then also act on the scrap in the lower tuyere free half of the converter. These tuyeres for the serving of one half of the converter bottom can be protected from melting, upon the introduction of the liquid pig iron with the converter horizontal, by introduction of an inert gas.
The present invention solves the overall problem of eliminating the generally substantial formation of smoke and flames by blowing inert gas (for instance nitrogen) in through the bottom tuyeres upon the charging of the scrap and, insofar as gases and vapors remain, preventing their emergence into the furnace room as well as the occurrence of red iron smoke upon the following pouring in of the pig iron.